<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input type="button" value="改变大小" onclick="window.resizeBy(-20,-20)">
<input type="button" value="改变大小" onclick="window.resizeBy(20,20)">
<script>
    window.onload = function(){
        window.resizeTo(window.screen.width,window.screen.height)
    }
</script>
</body>
</html>